You want to go small on the tank. The tank should have 2 snug fitting hides, and a water bowl. Keep it simple, they do not need anything fancy. The tank should be just big enough to fit the hides and water bowl, with very little room elsewhere. Ball pythons can get stressed when given too much space. If you get a larger tank than needed make sure to clutter it up with more hides or foliage. I would highly recommend not getting the tank setup and the snake on the same day. You should have the tank completely set up at least a few days before bringing the snake home so you can make sure your temps and husbandry are spot on. That's about all I have for now. If you have any more specific questions such as heating methods, etc. be sure to ask.